(1) Field of the Invention
This invention relates to the isomerization of aldehydes, such as isobutyraldehyde, to ketones, such as methyl ethyl ketone (MEK).
(2) Description of the Prior Art
Canter et al, U.S. Pat. No. 3,384,668, teach the isomerization of aliphatic aldehydes to ketones by contacting a vaporous aldehyde with a solid acidic catalyst, e.g., phosphoric acid on a support, at a temperature above 100.degree. C.
Hargis et al, U.S. Pat. No. 3,453,331, teach the production of symmetrical and unsymmetrical ketones from aldehydes by contacting an aldehyde with an oxidized form of a rare earth metal having an atomic number of 59 to 71 supported on an activated alumina. The process is a vapor-phase process.
Velenyi et al, U.S. Pat. No. 4,329,506, teach that aldehydes, such as isobutyraldehyde, are isomerized to ketones, such as methyl ethyl ketone, by contact at isomerization conditions, typically vapor-phase conditions, with a catalyst of the formula M.sub.0.15-15 M'.sub.0.05-12 O.sub.x where M is at least one of Mo and Cu and M' is a promoter, such as a Group IIB or VIII element.
S. A. Lange et al, "Isomerization of Isobutyraldehyde to Methyl Ethyl Ketone", Neftekhim. 16, No. 6, 818-822 (1976) [Russian] teach the skeletal isomerization of isobutyraldehye to methyl ethyl ketone in the presence of zeolite-containing aluminosilicate catalysts, HY Zeolites, in a stream of steam. They report that the selectivity of MEK formation passes through a maximum at a temperature of from 450.degree. to 470.degree. C. and that the presence of water in the raw material feed significantly enhances the yield of MEK.